It says install sucessful, than it rebooted itself. Now, when I boot it up from the hard drive, it says, your computer has to be restarted(The grey screen). I tried to even boot up from the USB stick again. No luck. Anyone know why?

By the sounds of it, one (or more) of your kext is causing it to panic and crash.

When you boot up, at the chameleon (or similar) screen, press F8. Now type "-v" (without the quotations) and press enter. It should then start to boot up. If there is a problem, then it should say. You could also type "-x" to boot up in Safe Mode. And then you could modify or install a new kext to stop the panic.